The present invention is directed to a vehicle recycling plant wherein scrap vehicles are at least partially disassembled, processed, and converted into suitable products. More particularly, the present invention is directed to a vehicle recycling plant for processing, for example, automobile bodies and automobile parts wherein the conversion of the vehicle body and vehicle parts into other products can be accomplished utilizing an inexpensive source of fuel and wherein the residual heat produced during the burning process can be effectively utilized to produce a number of functions. The vehicle processing plant of the present invention makes maximum use of the heat generated during the melting down of the vehicle without measurably contributing to air pollution.
Steel mills require high density high grade scrap for use as charges for steel furnaces in order to produce the requirements of industry. Unfortunately, it is extremely difficult to obtain sufficient quantities of high grade steel scrap because the sources of such scrap are heavily contaminated with materials adversely affecting the physical and chemical characteristics of any steel produced from such scrap.
One of the major sources of such low grade scrap steel is discarded or junked automobile bodies which have been mechanically densified in various ways. It is, for example, common practice to first dismantle the bodies by physically removing the doors, trunk lids and engine hoods, and then cut up the remainder of the body and/or frame to provide relatively large panels or sections which may then be mechanically shredded with mangling devices to produce smaller metal fragments. These fragments are then sometimes processed through a magnetic separating apparatus to roughly sort the basically ferrous from the nonferrous metals. The shredded materials, whether separated or not, may then be compressed by presses or drop hammers into sheets of material which subsequently may be sliced into strips and then baled. Sometimes the shredded material is baled directly, and in some cases the large sections are compressed into a bale without having been first shredded. In any event, all of these methods result in relatively low density, highly contaminated scrap material.
A number of processing plants for processing vehicle bodies into scrap or for converting vehicle bodies into reusable steel or high grade pig ore are well known in the art. However, the present processing plants suffer from a number of deficiencies. For example, the source of fuel utilized in said plants is frequently very expensive and furthermore, effective use is not made of the heat produced in the melting furnaces. In addition, because of the current emphasis being placed upon the elimination of air pollution, it is essential that vehicle processing plants provide an effective means for removing the various pollutants from the end of the flue disposed downstream of the furnace.
In some cases, attempts to reduce the contaminants by burning of the discarded automobile bodies has been attempted, but the results have not been satisfactory because of the relatively low temperatures achievable by open dump type burning. Moreover, most communities now prohibit such burning procedures under the air pollution statutes and ordinances. The low grade of scrap which consequently results from the aforedescribed treatments of discarded automobile bodies is not readily salable so that such old and discarded automobile bodies are not in demand for scrap salvage purposes. As a result, more and more communities are finding themselves with large numbers of old abandoned cars accumulating on their streets and roadways, and salvage yards are finding it more and more difficult to dispose of such car bodies when they have been stripped of whatever salable parts were salvageable.
Accordingly, an object of the present invention is to provide an improved vehicle recycling plant wherein an inexpensive source of fuel is utilized for providing the necessary heat for melting down vehicle bodies.
Another object of the present invention is to provide an improved vehicle recycling plant wherein effective and efficient use is made of the heat which is exhausted from the furnace.
A further object of the present invention is to provide a flue which is associated with said furnace which is effective in converting the heat exhausted from the furnace into usable energy while at the same time substantially eliminating particles in the flue so that the exhaust from the recycling plant substantially meets pollution standards and requirements.
Still another object of the present invention is to provide a substantially continuous vehicle recycling plant wherein effective use is made of all of the various types of metals and other materials which can be found in a vehicle which is destined for scrap.
Other objects and further scope of applicability of the present invention will become apparent from the detailed description given hereinafter; it should be understood, however, that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.
Pursuant to the present invention, the above-mentioned disadvantages may be eliminated and a much improved vehicle recycling plant has been developed wherein scrap vehicles are disassembled and processed to produce a variety of metal products and wherein effective use is made of the energy produced during the recycling process. According to the present invention, scrap vehicles are first disassembled and separated into their various component parts. First of all, for example, the rubber tires are removed from the vehicles. These rubber tires are then utilized as an inexpensive source of fuel for the furnace and are particularly effective in that a temperature of about 2400.degree. F. can be achieved in the furnace in the burning of said tires. Of course, the furnace is provided with a plurality of burners which are used to start the combustion in the furnace and in some instances, supplement the heat source provided in the furnace. The furnace can be of any well known design but should be sufficiently large to accommodate about 450-500 tires at one time. Advantageously, the bottom portion of the furnace slopes inwardly so that the steel beads contained in the ash produced by the burning of steel belted tires can be recovered by a container disposed below an aperture provided where the sloping surfaces of the bottom portion of the furnace approach each other. Also, said sloping surfaces are provided with a plurality of apertures through which the ash is removed from the base of the furnace. Advantageously, the sloping surfaces of the base of the furnace can be provided with means for vibrating said surfaces much in the manner of a vibrating hamper. This vibration facilitates the removal of both the ash and the steel beads from the bottom of the furnace.
The scrap vehicle body is further stripped of other components, such as alternators, radiators, generators, starters, voltage regulators, transmissions, carburetors, glass, and the like, which are processed separately in a different portion of the recycling plant of the present invention. Thus, the vehicle bodies, stripped of all of the above components are continuously introduced on a conveyor belt positioned above the top of the furnace for eventual dumping into a cupola where the melting down of the vehicle bodies is completed. The vehicle bodies are conveyed above the furnace so that the radiant heat produced by the furnace can be used to burn up all of the undesirable materials such as wood, upholstery, carpeting, undercoating and the like, which would tend to contaminate the resulting molten metal product. Also the radiant heat begins the vehicle melting down process.
Thus, by the time the vehicle reaches the end of the conveyor system for dumping into the cupola, the melting process has substantially begun. The exhaust provided for the furnace communicates with the cupola and is located in the vicinity where the vehicle body is discharged from the conveyor belt into the cupola so that the heat contained in said exhaust is effectively used to provide a further high temperature environment for melting down the vehicle bodies as they are discharged from the conveyor belt into the cupola. The walls of the furnace and cupola are formed from layers of refractory material, e.g., refractory brick.
As a supplemental source of heat for the cupola, carbon electrodes are suspended from above the cupola and are adapted so that they can be raised or lowered so that they can be placed into close proximity with the surface of the molten steel. Thus, the carbon electrodes can be lowered to a position just above the surface of the steel and are utilized to finish off the melt, that is, to convert the scrap vehicle bodies completely into a liquid form. The carbon electrodes generate off current of about 32,000 KBA and increase the temperature in the cupola to about 3,200.degree. F. Not only is this additional heat effective in finishing off the molten steel in the cupola, but it is also effective in burning the contaminants carried in the flue gas. When a sufficient level of molten steel is achieved, the hot metal is drained from the bottom of the cupola into holding tanks disposed on a conveyor belt. Advantageously, the bottom surface of the cupola container is sloped to facilitate the transfer of the molten steel to the holding tanks. In the holding tanks, the molten steel separates into a lower steel level and an upper slag level. Thus, the conveyor belt can be utilized to transfer the holding tanks to a rolling mill where the steel in said tanks can be drawn off and used to manufacture light structural materials, such as, for example, reinforcing bars, fence posts, and the like. The slag which still remains in the holding tanks can then be dumped. The holding tanks can then be recycled back to the cupola for another load of molten steel. Alternatively, the cupola can be periodically tapped to draw off the molten metal into pig or billet forming molds and the slag is separately tapped and disposed of in any desired manner, such as, for example, as sanitary fill or for aggregate for concrete mixes.
The hot gases which are being drawn from the furnace and from the zone above the molten steel and the cupola are drawn into a substantially horizontal flue which is made of fire brick and is adapted to accomodate a number of devices which make further use of the very hot exhaust gases. For example, the flue is provided with a compartment, e.g., a copper smelter which is completely disposed within and surrounded by the flue gases so that the surfaces of said smelter make maximum use of the heated gases being circulated therearound. For example, the alternators, radiators, generators, starters, voltage regulators and any other copper containing elements found in the vehicle are introduced into the copper smelter. The heat flowing through the flue is thus utilized to melt said elements introduced into the copper smelter. Once the copper elements have been smelted, the molten product can be removed from the bottom portion of the smelter.
Advantageously, the copper smelter can be followed in succession by a zinc smelter, a glass smelter and one or more additional smelters, as desired. These smelters are substantially equivalent to the copper smelter and are utilized for converting scrap products into usable products. For example, the zinc smelter is adapted to receive motors, transmissions and carburetors which are high in zinc content and convert said elements to molten zinc which can be eventually used in a variety of ways. Downstream of the smelters, the flue can be further provided with a number of heating exchange units which are adapted to convert the remaining heated gas traveling through the flue into a number of uses, such as, for example, converting water to steam to run a generator plant or further utilizing said heated gas through the effective use of steam coils to function as a sawdust dryer or a grain dryer.
Downstream of the heat exchange units, the hot flue gas must be cooled down and further cleaned up before it is discharged to the atmosphere. Accordingly, the flue is provided with an enlarged section which fits around the end portion of the smaller flue section thereby defining a zone between said sections for introducing air therebetween.
In other words, because said enlarged section is larger than the existing flue, it fits around said flue leaving an open area between the outer circumference of the flue and the inner circumference of the enlarged section for the introduction of air into the system. Furthermore, the enlarged section is provided with a number of air vents which are angled in the direction of the flow of the heated flue gas. Thus, the air being introduced axially at the beginning of the enlarged section, as well as the air introduced through the air vents causes a complete mixture of the cooler ambient air with the hotter flue exhaust gas thereby substantially reducing the overall temperature of the exhaust gas. Also, because of the turbulence created by the air introduced through the air vents, the exhaust gas in said enlarged section has a substantially uniform temperature throughout. Downstream of the air vents, the enlarged section is further provided with a plurality of spray nozzles which are utilized to remove particulate matter and other pollutants from the exhaust gas. The end of the flue is provided with an exhaust pump which functions to draw the exhaust gas from the furnace and through the flue to eventual discharge to the atmosphere. The exhaust pump also draws the cooler ambient air into the enlarged section of the flue. Also, because of the vacuum produced by the pump, the temperature of the gases produced in the furnace is naturally increased.